****DEVELOPERS SAY THIS IS AN OUTDATED RENDERING...DJ****Undated handout renderings from Pelli Clarke Pelli Architects shows a proposed 10-story building on the Embarcadero next to the Audiffred Building, a historic 1889 brick landmark that houses the restaurant Boulevard. This rendering shows what 110 Embarcadero would look like from the north east.

Photo: Pelli Clarke Pelli Architects, Courtesy To The Chronicle

****DEVELOPERS SAY THIS IS AN OUTDATED RENDERING...DJ****Undated...

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Undated handout renderings from Pelli Clarke Pelli Architects shows a proposed 10-story building on the Embarcadero next to the Audiffred Building, a historic 1889 brick landmark that houses the restaurant Boulevard. This rendering shows what 110 Embarcadero would look like from the north east. Pelli Clarke Pelli Architects / Courtesy to The Chronicle

Undated handout renderings from Pelli Clarke Pelli Architects shows a proposed 10-story building on the Embarcadero next to the Audiffred Building, a historic 1889 brick landmark that houses the restaurant Boulevard. This rendering shows what 110 Embarcadero would look like from the Embarcadero. Pelli Clarke Pelli Architects / Courtesy to The Chronicle

Now that "green" buildings are all the rage, San Francisco could see the real thing sprout on the Embarcadero: a glass office building scaled by vines that change color with the seasons.

The proposed 10-story building would rise from a sliver of land next to the Audiffred Building, a three-story brick landmark from 1889 that houses Boulevard Restaurant. Unlike the Audiffred - a French-flavored confection and downtown's oldest waterfront structure - the look next door would be all clear glass and straight lines.

While some tweaks are needed, the project has the potential to be the most exquisite addition to the waterfront since the Embarcadero Freeway came down in 1991 - a poised counterpart to the Audiffred and other nearby landmarks, softened by a lacy living weave that symbolizes today's emphasis on environmental concerns.

The architect and developer of what is dubbed 110 The Embarcadero is also the team that won last year's competition to erect San Francisco's tallest tower. The target opening date for that building is 2013; however, developer Hines wants to take its Embarcadero project to the Planning Commission for approvals this spring, start construction this fall and open in late 2009.

Despite the disparity in size, this miniature isn't an afterthought. If anything, it shows a better understanding of San Francisco's landscape and the challenge of growing in a way that neither apes the past nor overwhelms it.

"This is one of the most adventurous projects we're looking at right now," said Fred Clarke of Pelli Clarke Pelli Architects, the Connecticut firm working for Hines. "At one level, it's a small building. At another, it tests all sorts of assumption about green design."

The structure would fill a 44-foot-wide site now occupied by a long-empty two-story building. There are seven other buildings on the block, including a handsome YMCA building from 1924 and forgettable filler from when the neighborhood was defined by an elevated freeway rather than a wide-open bay.

The design by Pelli Clarke Pelli keeps things simple, a tall box with glass on all sides except the south, where the floors that poke above a six-story neighbor would be clad in solar panels.

The eye-catching feature would be the outer layer of green.

Planters contained by a trellis-like mesh would be attached between each floor, and each planter would hold a mix of vines so something is in bloom each month of the year. The vines would be trained to snake around cables that would form a sort of taut net around the glass box, with vertical cables spaced every 5 feet and horizontal ones stretched waist-high across each floor.

Not only would the vines provide a sort of environmental ornamentation, they'd help cool the exterior and reduce energy needs.

The vegetation and the solar panels are the most obvious signals of 110 The Embarcadero's emphasis on sustainability. Clarke and Hines say the goal is to earn a Platinum rating from the U.S. Green Building Council. That's the top honor given by the council, and it has yet to be applied to a speculative office building.

This sort of fine-grain infill isn't what you'd associate with the design firm founded by Cesar Pelli, best known for such sky poppers as Petronas Towers in Malaysia, the world's tallest buildings from 1996 until 2003. Nor Hines, a Houston developer that makes a specialty of marquee projects by brand-name architects.

But Hines bought the site in 2006, drawn by a visibility and location that can't be duplicated. As for Pelli and Clarke, you sense they relish the shift in scale from skyline peaks to mid-block lots.

"The site is so constrained it wasn't a place for dramatic moves," Clarke said. "We saw the potential for something very crisp and elegant."

Pelli and Clarke also use the word elegant to describe their proposed obelisk-like Transbay Tower. But when you're talking about a building that could be 300 feet taller than the Transamerica Pyramid - the final design is months or years away - elegance is outweighed by sheer size.

Here, by contrast, the firm has the chance to do what Pelli does best: home in on the details that make a building memorable no matter what the shape or height might be. For instance, a narrow vine-free bay would project slightly above the retail space on the Embarcadero and proceed up the building to give the profile an extra snap.

The same creativity is applied to the sustainable design features. Cables supporting the vines would also be used to irrigate the planters, recycling filtered wastewater from the building. Douglas fir piers beneath the structure on the site would return as the decking for a publicly accessible rooftop open space.

The one clumsy piece of all this is the height.

Ten stories is hardly a skyscraper, but what's proposed is out of proportion to the Audiffred Building. Add the vine-clad rooftop mechanical system, and the building pushes past the YMCA's peaked roof.

A better approach is to show a bit of deference and come down a story or two below what's currently proposed. Hines would still have a building tall enough to stand out, but it would do so with the subtlety that characterizes the rest of the project.

That's a relatively small change for a relatively small building that, done right, could loom large in all the right ways - demonstrating that cities can evolve with grace while embodying the need for environmental responsibility.

If we're lucky, 110 The Embarcadero will teach us a lesson architecturally as well. The best way to complement historic landmarks isn't to mimic them. It's to add equally good buildings of our era to the mix.

Get involved

No hearings are scheduled on the proposed Embarcadero building, but the issue will eventually be before the Planning Commission.

Contact the Planning Department at 1650 Mission St., Suite 400, San Francisco, CA 94103 or by phone at (415) 558-6378.